Electric gaseous discharge lamp



l Juy 26, 1949. c. HERZOG ELECTRIC GASEOUS DISCHARGE LAMP 2 Sheets-Sheet 1 Filed Jan. 24, 1945 H07 All? D/Jc/Mfrcf July 26, 1949. c. HERZOG ELECTRIC GASEOUSDISCHARGE LAMP 2 Sheets-Sheet 2 Filed Jan. 24, 1945 Patented July 26, 1949 v UNITED STATES PATENT OFFICE ELECTRIC GASEOUS DISCHARGE LAMP Carl Hezog, Belleville, N. J. Y

Application January 24, 1945, Serial No. 574,306

u e claims. (ci. 17o-12s) My invention relates to electric gaseous discharge lamps, and to a method oi producing the same.

An important object oi the invention is to provide a glass disc or base for closing the end of the glass tube or envelope, and having the leads embedded thereinand also provided with a. metal ring which may be heated by electrical induction and which will in turn heat and plasticize the glass tube or envelope.

A further object of the invention is to provide a hot electrode discharge lamp which may be vacuum sealed by employing internal and external heating elements heated by electrical induction.

A further object ot the invention is to'provlde an electric discharge lamp having the glass tube welded to a metal part o! the disc or base, in a secure manner, overcoming tendency to breakage.

A further object o! the invention is to provide an electric discharge lamp which will lend itself to production by a simplied method of vacuum sealing.

Other objects and advantages oi' the invention will be apparent during the course of the following description.

In the accompanying drawings forming a part oi this application and in which like numerals are employed to designate like parts throughout the same,

Figure 1 is a central vertical longitudinal sec tion through a tubular electric discharge lamp, showing its ends held within operating units, parts in elevation,

Figure l* is a transverse section taken on line il--l of Figure 1,

Figure 2 is a central longitudinal section through one end o! the lamp, showing the glass welding step,

Figure 3 is a similar view showing the glass severing step,

Figure 1b is a transverse section taken on line Ib-Ib of Figure 8, Y

Figure 4 is a central longitudinal section through the completed electric discharge lamp, parts in section,

Figure 5 is a central longitudinal section .through one end of the discharge lamp embodying a modiiled form of the invention, prior to the glass welding step,

Figure 6 is a central longitudinal section through the completed electric discharge lamp, embodying the modied form of the invention, parts broken away,

Figure 6* is a transverse section taken on line 8*-6 of Figure 6,

Figure 7 is a central longitudinal section through one end of a third modiiied form ot lamp embodying my invention and prior to the welding Step' Figure 8 is a central longitudinal section through one end o! the completed electric discharge lamp embodying the third form of the invention, parts in elevation,

Figure 9 is a similar view of the opposite end, further parts in section, and,

Figure 8l is a transverse section taken on line 8*-8 oi Figure 9.

In the drawings, wherein `for the purpose of illustration are shown preferred embodiments of my invention, the numeral I0 designates a cylindrical glass tube, constituting the envelope of the hot electrode iluorescent lamp. This tube may be of any suitable diameter and length. The inner surface of the tube is covered or coated with a coating composition il containing a ilnely divided luminescent or iluorescent material, and this coating is dried. I may employ the coating composition disclosed in the patent to T. M. Cortese, 2,318,060, and this coating may be applied in accordance with the method disclosed in the Cortese patent. The tube I0, Figure 1, has the fluorescent coating composition Il of the Cortese patent extending to points i2, the end portions I3 and I4 oi the tube I0 having the coating removed and being clean or uncoated.

An electron emitting device Il is arranged within each end portion of the glass tube I0, and is held therein in spaced concentric relation prior to the glass welding, and while the interior of the glass tube is under vacuum. Each device i5 comprises a relatively thick and strong cylindrical disc or base I6, preferably formed of glass. This disc or base has stout leads I'l embedded therein and extending axially through the same and having a vacuum tight joint therewith. At their inner ends, these leads I1 carry a hot or glow electrode I8. The hot electrode may comprise a coiled tungsten wire, coated with one or more oi' the alkaline earth oxide. This form of hot electrode for an electric discharge lamp is shown in Patent 2,322,224 and Patent 2,067,746. Any other suitable type oi hot electrode may be employed.

The numeral I9 designates a cylindrical retainer which is made of a special commercial chrome-iron alloy which has the same expansion coeflicient as glass. This retainer includes an outer ring 20, of smaller diameter than the tube III and an inner ring 2|, these rings being connected by an ed22. The glass base I6 is arranged within and welded to the inner ring 2| and has a vacuum tight joint therewith.

Each device I5 is supported, during the vvacuum period, by metal holders 23, having split resilient sockets 24, for holding the outer ends of the vmetal leads I1 and having detachable clamping engagement therewith. The holders 23 are v mounted upon and insulated from the ends 25 and 26 of operating units 21 and 23.

The numeral 29 designates a cylindrical insulating disc, made o! Bakelite or the like and having two tubular metal terminals 30 riveted vlike and the opposite ends of the tube are open. hThe upper end of the tube I9 is inserted into the operating unit 29 and its lower end into the operating unit 21. These operating units are identical to the operating units I9 and 20 of my co-pending applicationfor Method of and Apparatus for making cold cathode fluorescent lamps or the like, nled March 1, 1944, Serial No 525,446, which issued December 25, 1945, as U. S. Patent 2,391,573, except that the holders -23 are different. The devices I5 are supported in the end portions of the tube I by the holders 23. The two electron emitting devices I are therefore supported within the end portions of the tube I0 and the outer rings 2l of the retainers are in spaced concentric relation to the tube. With the parts thus arranged, the dried coating II may be baked by circulating heated airl through the tube I0, as disclosed in my said co-pending application, or the baking may be effected in an oven prior to the arrangement of the tube I0 in the operating units. v The lower end of the tube I0 is now placed in communication with a source of vacuum and the tube evacuated and this vacuum is held on the tube while its opposite ing step is discontinued after a suitable time.

'Ihe suitable vacuum is still maintained within the tube I0 and a high frequency` electric coil A is now brought into position for surrounding the lower end of the tube I9 and the lower retainer I9. A carbon ring B is arranged between the coil A and thev tube Il, and ring` 20, ring B and coil A are in alignment. When an alternating current is turned on the coil A, current is induced in the exterior ring B and the interior ring 20, and these rings are highly heated. The heat is radiated outwardly from the ring 20 and radiated inwardly from the ring B to the glass tube I0, Figure 2. This glass tube is accordingly heated and plasticized and due to the presence of the vacuum in the tube III, the heated portion of the tube is drawn inwardly, Figure 2, and coni ltacts with the ring 29 and is welded to the ring.

The current may now be turned off from the coil 32'. The glass tube I Il is welded to the ring 20 to form a vacuum-tight joint therewith. M

A small amount of an inert gas, such as argon or neon may now be supplied into the upper end of the tube I0, and after this is done. a measured amount of mercury may be supplied into the upper end of the tube III and will drop to the'bottom thereof. The gas and mercury may be supplied in the manner disclosed in my said co-pending application.

The tube I0 still has the vacuum therein and another high frequency coil A and another ring B are positioned adjacent to the upper ring 20.

Current isnow supplied to the upper coil A and the tube I0 is heated and welded to the upper ring 20 and subsequently severed, in the manner described in connection with the lower electrode.

After the glass welding steps are completed, the tube III is separated from the operating units 21 and 28 and coils A and rings B, and the discs 29 are pressed into the recesses 3| and have a press-lit therein, .and the tubular terminals 30 applied tothe outer ends of the leads I1 and pinched thereon.

Figure 4 shows the completed electric discharge lamp. The ends of the glass tube IIl are welded to the metal rings 20 having the same coefficient of expansion as the glass and forming a vacuumtight joint with the glass tube. The thick glass base I8 carries the leads I1, and the disc 29 adds to the all-over thickness of the base and carries the tubular terminals 30.

' In Figures 5 and 6, the leads I1 are embedded in a cylindrical glass base 33, having the all-over desired thickness, since the insulating disc 29 is dispensed with. The leads I1 carry the electrode I8. A metal retainer including a ring 34 is provided, and this ring is formed of a special commercial chrome-iron alloy having the same coeicient of expansion as the glass tube. The base is welded to the ring 34 for forming a vacuum-tight joint therewith and the base 33 has its inner portion 35 molded to project over the end of the ring 34 and is ilush with the circumference of the ring 34. The base 33 is secured to the ring 34 before the assembled unit I5 is mounted in the tube I0.

The same method steps are followed in welding the ends of the tube I0 to the rings 34 as described. in connection with the rst form of lamp. When the ftube I0 is welded to the ring 34, Figure 6,. there is a glass-to-glass weld at 35e, thus providing a continuous glass surface, which greatly strengthens the construction. All of the method steps recited in connection with the 'production of the rst form of lamp are employed.

In Figures 5 and 6, the numeral 35' designates tubular metal terminals, mounted upon the leads I1, and having their inner ends embedded within and -welded to the glass base 33, to strengthen the construction. These tubular terminals are also squeezed to the leads I1.

In Figures 7, 8 and 9, I have shown a third modification oi' the invention. In'these iigures thev numeral 35b designates a cylindrical glass base having the all-over desired thickness and this base has the leads I1 embedded therein. This base is surrounded by a metal retainer or ring 36, formed of a special commercial chromeiron alloy, having the same coelcient of expansion as the glass. The base 35 is welded to the metal retainer or ring 36 and the upper end of the base extends beyond the retainer 36 and is molded to provide an end portion 31, extending radially beyond the retainer and also extending :amava axially inwardly over the same for a short distance. This end portion 31 is welded to the retainer or ring 3 8.

When the end of the tube III is welded to the metal retainer or ring Il, the end l1 is also welded to the tube in and provides a glass-tw glass weld 3B and a continuous glass surface which serves to strengthen the construction.

Tubular metal terminals 30 receive the leads I1 and have their inner ends embedded within and welded to the glass base il. These tubular terminals are squeezed to the leads, and the leads carry the electrode I8.

In the production of the third form of lamp all of the method steps recited in connection with the production of the first form of lamp are used.

The second and third forms of lamps are identical with the first form of lamp, except in the particulars herein pointed out. The same tube i0 with its coating, the same electrodes Il, and the same leads l1 are employed. In each form of lamp, a base is provided which carries the leads and terminals and this base has a wide cylindrical surface or -periphery which is welded to the tube III. This provides a strong construction and the base carries the terminals, and the usual outside -insulating cap or base carrying terminals is eliminated. In each form of lamp, the metal carrier or ring has the same coeillcient of expansion as the glass base and glass tube.

In the use of the holders 23 in connection with the second and third forms of the invention, the resilient sockets 24 will be somewhat enlarged, for receiving the tubular terminals 35' and 3l.

It is to be understood that the forms of my invention herein shown and described are to be taken as preferred examples of the same and that various changes in the shape, size, and arrangement of parts may be resorted to without departing from the spirit of my invention or the scope of the subjoined claims.

Having thus described my invention, what I claim is:

1. An electric discharge device comprising a glas-s tube having one end open, a, glass base, a metal retainer comprising spaced inner and outer rings, the inner ring receiving the glass base which is welded to the inner ring, the outer ring being arranged within the glass tube and having the glass tube welded to it, leads embedded in the glass base, an insulating disc mounted upon the outer face of the glass base, tubular terminals carried by the insulating disc and receiving the outer ends of the leads, and a hot electrode carried by the inner ends of the leads.

2. An electric discharge device comprising a glass tube having one end open, a wide glass base, a metal ring applied to the periphery of the glass base and having the glass base welded to it, the glass base being arranged within the open end of the glass tube and the glass tube welded to the metal ring, leads embedded in the glass base, tubular terminals receiving the outer ends of the leads and having their inner ends welded to the glass base, and a hot electrode carried by the inner ends of the leads.

3. An electric discharge device comprising a glass tube having an opening, a glass base, a metal ring receiving the glass base at its periphery and having the glass base welded to it, the glass base extending beyond one end of the metal ring, the glass base having a substantial width, the glass base being arranged within the glass having the glass base welded thereto, one end of the glass base projecting beyond the metal ring and having its, material extending over the vperiphery of the ring for a short distance, the glass tube being welded to the ring and the projecting portion of the glass base, leads embedded in the glass base. tubular terminals receiving the outer end of the leads and engaging the glass base, and hdost electrode carried by the inner ends of the 5. An electric discharge device comprising a glass envelope having an opening, a. metal retainer, a glass base arranged within the metal retainer and welded to the same, leads embedded in the glass base, an electrode carried by the leads, the metal retainer forming a recess upon the outer side of the glass base, the metal retainer being arranged within the opening and welded to the glass envelope, an insulating disc inserted within the recess, and tubular terminals carried by the insulating disc and receiving the leads therein.

6. Anr electric discharge device comprising a glasstube. having one end open, a metal retainer arranged within the open end of the glass tube and including spaced inner and outer rings, the outer ring being welded to the glass tube, a glass base arranged within the inner ring and welded to the inner ring, the inner ring forming a recess upon the outside of the glass base, leads embedded in the glass base, an electrode carried by the leads, an insulating disc arranged within the recess and having a press llt therein, and tubular terminals attached to the insulating disc and receiving the leads.

'1. An electric discharge device comprising a glass tube having one end open, a substantially cylindrical metal retainer shell mounted within the open end of the glass tube and having substantially the same coeilicient of expansion as the glass tube, the 7glass tube being welded to .the

metal retainer shell and the end of the glass tube extending vsubstantially to the outer end of the retainer shell, a thick glass disc arranged within and welded to the metal retainer shell, stout leads embedded within the glass disc and extending beyond the inner and outer faces of the glass disc, tubular terminals receiving the outer ends of the leads, and an electrode carried by the inner ends of the leads. Y

8. An electric discharge device comprising a glass tube having lone end open, a substantially cylindrical metal retainer shell mounted within the open end of the glass tube and having substantially the same coeilicient of expansion as the glass tube, the glass tube` being welded to the metal retainer shell and the end of the glass tube extending substantially'to 'the outer end of the retainer shell, a. thick glass disc arranged within and welded to the metal retainer shell and having its outer face substantially ilat, stout leads embedded within the glass disc and being of substantially the same length and extending beyond the inner and outer faces of the glass disc, the

, leads being spaced radially inwardly from .the

outer ends or the ends, and an electrode carried.

by the inner ends of the leads. v

9. An electric discharge device comprising a glass tube 'having one end open, a metal retainer shell having substantially the same coeliicient oi expansion as the glass tube. said shell including an outer ring, an inner ring spaced from the outer ring and an end connecting the inner and outer rings, the retainer shell being mounted within the open end of the glass t-ube and the glass tube welded to the outer ring, a glass disc arranged within the inner ring and welded thereto, leads embedded in the glass disc and spaced radially inwardly from the inner ring. an electrode carried by the inner ends of the leads, and tubular terminals receiving the outer ends of the leads.

CARL HERZOG.`

REFERENCES crrED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number N Date 1,657,208 Grealsl Jan. 24, 1928 1,716,140 Kirwei June 4, 1929 2,006,818 Zimber July 2, 1935 2,077,199 Asmussen Apr. 13, 1937 2,137,174 Marshaus Nov. 15, 1938 2,138,224 Barasch Nov. 29, 1938 2,154,550 White Apr. 18, 1939 2,175,361 Reger Oct. 10, 1939 2,267,318 Aicher v Deo; 23, 1941 2,271,657 Miller Feb. 3, 1942 2,322,224 Cox June 22, 1943 2,418,179 Isaac 'Api'. 1, 1947 FOREIGN PATENTS Number Country Date 527,940 Great Britain Oct. 18, 1940 

